4,000 is the backstreet price in yuan/renminbi in Beijing for an empty
bottle of 50-year-old Kweichow Moutai — the highest-end (if tonsil-sanding)
version of the famous baijiu liquor.

Normally, 50-year-old Moutai legitimately retails for about RMB40,000 (£4,000)
per 50cl bottle. Alarmingly for Moutai, empty bottle prices may be about to
soar.

China’s brisk trade in used Moutai bottles is the life blood of a rarefied
line in crookery — counterfeit premium liquor operations, which refill the
authentic ceramic flasks with fake grog and sell them as the real thing at a
gloriously excessive mark-up.